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Gonzalo Ayuso is a Web Architect with more than 10 year of experience in the web development, specialized in Open Source technologies. Experienced delivering scalable, secure and high performing web solutions to large scale enterprise clients. Blogs at gonzalo123.com. Gonzalo is a DZone MVB and is not an employee of DZone and has posted 53 posts at DZone. You can read more from them at their website. View Full User Profile

Building a Simple TCP Proxy Server with node.js

09.20.2012
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Today we're going to build a simple TCP proxy server. The scenario: we've got one host (the client) that establishes a TCP connection to another one (the remote).

client —> remote

We want to set up a proxy server in the middle, so the client will establish the connection with the proxy and the proxy will forward it to the remote, keeping in mind the remote response also.
With node.js is really simple to perform those kind of network operations.

client —> proxy -> remote

var net = require('net');

var LOCAL_PORT  = 6512;
var REMOTE_PORT = 6512;
var REMOTE_ADDR = "192.168.1.25";

var server = net.createServer(function (socket) {
    socket.on('data', function (msg) {
        console.log('  ** START **');
        console.log('<< From client to proxy ', msg.toString());
        var serviceSocket = new net.Socket();
        serviceSocket.connect(parseInt(REMOTE_PORT), REMOTE_ADDR, function () {
            console.log('>> From proxy to remote', msg.toString());
            serviceSocket.write(msg);
        });
        serviceSocket.on("data", function (data) {
            console.log('<< From remote to proxy', data.toString());
            socket.write(data);
            console.log('>> From proxy to client', data.toString());
        });
    });
});

server.listen(LOCAL_PORT);
console.log("TCP server accepting connection on port: " + LOCAL_PORT);

Simple, isn’t it?
Source code in github

 

 

 

Published at DZone with permission of Gonzalo Ayuso, author and DZone MVB. (source)

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